The surface properties of building façades have implications for thermal performance of buildings and might also influence outdoor thermal comfort conditions for pedestrians. A surface property, which is frequently used by building engineers and specially architects, is the visual reflectance. In this dissertation, effects of façade visual reflectance on thermal aspects of building performance as well as outdoor thermal comfort have been investigated in four parts. In the first part, the result of a field study, which explores the relationship between the visual reflectance of actual building façades and the corresponding surfaces temperatures, is presented. A number of buildings with diverse façade colors were selected. Surface temperatures via infrared thermography and façade visual reflectance via simultaneous monitoring of the illuminance on the façades and the luminance values of the façade as well as incident solar radiation, ambient air temperature and relative humidity were measured. The results of the field study display non-random relationships between the building façades visual reflectance and their surface temperatures. The second part of the research is dedicated to calibration of a computer-aided simulation tool via the empirical information. For this purpose, a number of the buildings on which measurements had been conducted were modeled. Using climatic data almost same to environmental conditions in which the corresponding empirical information had been collected, outer surface temperatures of the modeled façades were simulated for same dates and hours. As the results of simulations matched the empirical data well, in third part of the research, by applying different values of visual reflectance to the façade of a simplified building model, indoor thermal performance of residential buildings was investigated. The results show that while amount of visual reflectance of the façades surface has little impact on indoor temperature and energy demand of buildings with polystyrene insulation, its effect on cooling load of non-insulated buildings is relatively considerable. Finally, in fourth part of the research impact of different façade colors on thermal comfort in pedestrian area was explored. An urban canyon based on simplified geometry of a typical street in the city of Vienna was modeled. Impact of visual reflectance of south-facing building façades on instantaneous mean radiant temperature and thermal comfort of area close to the façade was investigated. The results indicate that dark façades with insulation beneath might considerably affect mean radiant temperature in pedestrian area.